It's well-established that air pollution is pretty bad for your lungs and body, but there may be some pretty serious side effects for your brain, too. New research published in Molecular Psychiatry looked at the effects of air pollution on mice and their behavior.

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Rodents exposed to polluted city air found it harder to learn and remember ordinary tasks.

The researchers had the unenviable job of submitting mice to air pollution on par with a heavily-polluted inner city for half of their natural life span - and then put them through learning and memory tests. The mice were trained to find an escape hole in a brightly lit arena to nice dark box. Those that had been exposed to pollution had a harder time learning where the escape hatch was, and were less likely to remember it. They were also more depressed and anxious than a control group.

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So, why is this happening? It boils down to the hippocampus. In that region of the brain there are things called dendrites, which grow off the neurons. These dendrites in turn have spines, which are used for sending signals between neurons. The pollution exposed mice had fewer spines and shorter dendrites — both of which are associated with worsened memory and learning.

Researchers think this is happening because pollution is associated with wide-grade, body-wide inflammation, which hits the brain too, damaging the hippocampus.